As has been pointed out, you can create subgroups in iJournal, but I strongly suggest you double-check your work via LiveJournal's Web interface. In both 1.47 and 1.48, I have witnessed garbled friends lists. I see people both in and out of the groups I've created as well as missing people who are there when I check my Info and friends pages on this site (and I do wish I could get more specific about this for the developers, but it's not easy).